The effectiveness of an online short-format Recovery College model: a co-learning model to support mental health.

BACKGROUND: Our societies are facing mental health challenges, which have been compounded by the Covid-19. This event led people to isolate themselves and to stop seeking the help they needed. In response to this situation, the Health and Recovery Learning Center, applying the Recovery College (RC) model, modified its training program to a shorter online format. This study examines the effectiveness of a single RC training course delivered in a shortened online format to a diverse population at risk of mental health deterioration in the context of Covid-19. METHODS: This quasi-experimental study used a one-group pretest-posttest design with repeated measures. Three hundred and fifteen (n = 315) learners agreed to take part in the study and completed questionnaires on wellbeing, anxiety, resilience, self-management, empowerment and stigmatizing attitudes and behaviors. RESULTS: Analyses of variance using a linear mixed models revealed that attending a RC training course had, over time, a statistically significant effect on wellbeing (p = 0.004), anxiety (p < 0.001), self-esteem/self-efficacy (p = 0.005), disclosure/help-seeking (p < 0.001) and a slight effect on resilience (p = 0.019) and optimism/control over the future (p = 0.01). CONCLUSIONS: This study is the first to measure participation in a single online short-format RC training course, with a diversity of learners and a large sample. These results support the hypothesis that an online short-format training course can reduce psychological distress and increase self-efficacy and help-seeking. TRIAL REGISTRATION: This study was previously approved by two certified ethics committees: Comité d'éthique de la recherche du CIUSSS EMTL, which acted as the committee responsible for the multicenter study, reference number MP-12-2021-2421, and Comité d'éthique avec les êtres humains de l'UQTR, reference number CER-20-270-07.01.

Learner Experience of an Online Co-Learning Model to Support Mental Health during the COVID-19 Pandemic: A Qualitative Study.

The COVID-19 pandemic has had a negative impact on the mental health of the population such as increased levels of anxiety, psychological distress, isolation, etc. Access to mental health services has been limited due to the "overflow" of demands. The Recovery College (RC) model, an education-based approach, has addressed this challenge and provided online well-being and mental health courses to at-risk populations. The RC model proposes a co-learning space in an adult education program where learners from diverse backgrounds collectively learn and empower themselves to better address psychological well-being and mental health issues. The aim of this study was to document the experience of learners who participated in online RC courses during the COVID-19 pandemic and the perceived impact of these courses on their mental health. A qualitative interpretative descriptive study design was employed, and Miles and Huberman's stepwise content analysis method was used to mine the data for themes. Fourteen structured online interviews were conducted with a sample representative of the diversity of learners. Five categories of themes emerged: (1) updating and validating your mental health knowledge, (2) taking care of yourself and your mental health, (3) improving and modifying your behaviors and practices, (4) changing how you look at yourself and others, and (5) interacting and connecting with others. Results suggest that online RC courses can be an effective strategy for supporting individual self-regulation and empowerment, breaking social isolation, and reducing the effects of stress in times of social confinement measures and limited access to care.

Ethical Issues in Research: Perceptions of Researchers, Research Ethics Board Members and Research Ethics Experts.

In the context of academic research, a diversity of ethical issues, conditioned by the different roles of members within these institutions, arise. Previous studies on this topic addressed mainly the perceptions of researchers. However, to our knowledge, no studies have explored the transversal ethical issues from a wider spectrum, including other members of academic institutions as the research ethics board (REB) members, and the research ethics experts. The present study used a descriptive phenomenological approach to document the ethical issues experienced by a heterogeneous group of Canadian researchers, REB members, and research ethics experts. Data collection involved socio-demographic questionnaires and individual semi-structured interviews. Following the triangulation of different perspectives (researchers, REB members and ethics experts), emerging ethical issues were synthesized in ten units of meaning: (1) research integrity, (2) conflicts of interest, (3) respect for research participants, (4) lack of supervision and power imbalances, (5) individualism and performance, (6) inadequate ethical guidance, (7) social injustices, (8) distributive injustices, (9) epistemic injustices, and (10) ethical distress. This study highlighted several problematic elements that can support the identification of future solutions to resolve transversal ethical issues in research that affect the heterogeneous members of the academic community.

Assessing Changes in Anxiety, Empowerment, Stigma and Wellbeing in Participants Attending an Online-Based Recovery College in Quebec During the Covid-19 Pandemic: A Pre-Experimental Study.

Objectives: The present study aims to evaluate the effect of an online Recovery College (RC) program implemented in Quebec (Canada) during the COVID-19 pandemic. From October 2020 to June 2021, 27 training groups were conducted with a total of 362 attendees. Methods: Outcome was evaluated using a single group repeated measure design, assessing participants prior the training (T0), after the training (T1) and at follow up (T2). 107 learners of the Quebec RC program attended three two-hour sessions agreed to participate to the research. Results: Overall findings show at T1 a small but statistically significant reduction of anxiety and increase in empowerment, and below threshold reduction of stigmatizing attitudes and increase of wellbeing. Conversely, the medium-term changes at follow up were non-significant for all the outcome dimension except for anxiety. Conclusion: Findings suggest that the RC online program can be considered as a potential effective strategy to support self-regulation and empowerment of individuals and to reduce anxiety in the context of crisis for the general population.

What If Deliberately Dying Is an Occupation?

In some legal and societal circumstances, people freely and capably plan, organize, and precipitate their own death. Drawing on published literature, we critically reflect on how deliberately ending one's own life fits with the current definitions of the concept of occupation. Using an occupational science and occupational therapy theoretical reflection, we argue that deliberately dying can for some people be considered a purposeful and meaningful occupation. Implications for such an occupational therapy practice are discussed: attending to the occupational needs of specific groups of people, reconsidering definitions and conceptual work, advocating for occupational justice in ending life activities, reflecting on ethical conundrums around self-harm activities within the scope of practice, and exploring deliberate death as a purposeful and meaningful occupation. Because deliberately dying is something that some people do, in this article we aim to open a dialogue within the field of occupational science and occupational therapy about this sensitive and potentially controversial issue.

What is Professionalism in Occupational Therapy? A Concept Analysis: Qu'est-ce que le professionnalisme en ergothérapie? Analyse de ce concept.

BACKGROUND.: Professionalism has been given different definitions over time. These are, commonly theoretical and difficult to operationalize. PURPOSE.: This study aimed to provide an operational definition of the concept of professionalism in occupational therapy. METHOD.: Based on a concept analysis design, a meta-narrative review was conducted to extract information from 30 occupational therapy manuscripts. FINDINGS.: Professionalism is a complex competence defined by the manifestation of distinct attitudes and behaviours that support excellence in the occupational therapy practice. In addition, professionalism is forged and evolves according to personal and environmental characteristics. The manifestation of professionalism can lead to positive consequences for occupational therapists, clients, and the discipline, notably contributing to a positive and strong professional identity. Moreover, professionalism is also subject to cultural influences, which leads to variations in its development, manifestations, and consequences. IMPLICATIONS.: This study offers a contemporary operational definition of professionalism and levers to promote its development and maintenance.

Structural Facilitators and Barriers to Access to and Continuity of French-Language Healthcare and Social Services in Ontario's Champlain Region.

Purpose: The purpose of this article is to examine access to and continuity of French-language healthcare and social services in Ontario's Champlain region through an analytical framework that incorporates people seeking care, their caregivers and the linguistic component of care into a health and social service system bounded by community, organizational, political and symbolic structures. Methods: Experiences of French-speaking seniors seeking care and those of health and social service providers and managers from two qualitative exploratory studies are used to describe trajectories through the system. Results: Participants exposed how, together with community vitality, issues within each of the system's symbolic, political or regulatory and organizational structures influence these trajectories. Conclusions: To meet the needs of francophone seniors, additional work is needed to increase French-language services coordination within the organizational, regulatory and policy structures of the health and social service system.

Waterborne outbreaks: a public health concern for rural municipalities with unchlorinated drinking water distribution systems.

OBJECTIVES: The objective of this study is to describe an important waterborne outbreak of gastrointestinal illness observed in a rural municipality of Quebec. METHODS: A population-based retrospective cohort study was conducted to identify risk factors associated with acute gastroenteritis. Indirect surveillance data were used to estimate the extent and the resolution of the epidemic. RESULTS: The cohort consisted of 140 randomly selected individuals of whom 22 met the illness case definition (15.7% attack rate). The epidemic curve was similar to the evolution of antidiarrheal products sold by the only pharmacy in town and calls made to the Health Info Line. Bivariate analysis led to identifying five risk factors of gastrointestinal illness: consumption of municipal water, contact with someone with acute gastroenteritis (within and outside of the household), contact with a child in daycare, and being less than 35 years of age. Drinking municipal water had the highest risk ratio (RR = 24.31; 95% CI = 1.50-393.4). Drinking water from a private artesian well was a protective factor (RR = 0.28; 95% CI = 0.09-0.90). CONCLUSION: This study highlighted that managing the risks associated with the consumption of untreated drinking water remains an important public health challenge, particularly in small rural municipalities vulnerable to climate variability.

Importance of Indigenous elders' contributions to individual and community wellness: results from a scoping review on social participation and intergenerational solidarity.

OBJECTIVE: Wellness is a challenge for Indigenous peoples, partly because Western services do not adopt a holistic approach. By devaluing traditional knowledge, Indigenous values and beliefs, these services lower Indigenous power and affect cultural identities. Indigenous elders participate in intergenerational solidarity by transmitting knowledge, values, and culture in a holistic approach. Despite widespread acceptance of the importance of Indigenous elders' contributions to wellness, a rigorous synthesis of knowledge has never been done. This study aimed to provide a comprehensive understanding of how Indigenous elders' social participation contributes to individual and community wellness. METHOD: A scoping review was conducted with Indigenous elders and stakeholders in Québec (Canada). Sixteen databases were searched with 57 keywords. Data from the documents retrieved were analyzed, organized, and synthesized based on the International Classification of Functioning, Disability and Health. SYNTHESIS: A total of 144 documents were examined, comprising 74 scientific papers and 70 sources from the gray literature. Indigenous elders contributed to wellness mainly through relationships and interactions with other community members and non-Indigenous people (72.2%); intergenerational oral and written communications (70.1%); community, social and civic life (45.8%); volunteering and jobs (35.4%); and family life (29.9%). Elders transmit traditional knowledge, strengthen social cohesion, and help to develop positive attitudes such as reciprocity. Their actions favour disease prevention and health promotion, as including traditional approaches increases the acceptability of health and social services. CONCLUSION: This scoping review highlights the need for longitudinal studies with mixed-method designs involving Indigenous communities at all stages of the research to deepen understanding of the contributions of Indigenous elders to individual and community wellness.

Sex differences in the evolution of left ventricle remodeling in rats with severe volume overload.

BACKGROUND: Aortic valve regurgitation (AR) results in left ventricle (LV) volume overload (VO) leading to its dilation and hypertrophy (H). We study a rat model of severe AR induced by puncturing one or two leaflets using a catheter. Most of our studies were conducted in male animals. Recently, we started investigating if sex dimorphism existed in the AR rat model. We observed that AR females developed as much LVH as males but morphological remodeling differences were present. A head-to-head comparison of LV morphological and functional changes had never been performed in AR males (M) and females (F) using the latest modalities in cardiac imaging by echocardiography. METHODS: We performed a longitudinal study to evaluate the development of LV hypertrophy caused by chronic AR in male and female rats over 6 months. Sham-operated (sham) animals were used as controls. RESULTS: LV diastolic volumes (EDV) increased more over 6 months in sham males than in females (38% vs. 23% for EDV, both p < 0.01). AR resulted in significant LV dilation for both sexes (54% vs. 51% increase in EDV) vs. baseline values. Since normal cardiac growth was less in females, dilation from AR was relatively more important for them (88% (M) vs. 157% (F) increase in EDV over sham). AR caused LV wall thickening in both males and females. It happened sooner for AR females and was more important than in males (25% (M) vs. 56% (F) increase in septum thickness at 2 months and 10% (M) vs. 30% (F) at 6 months). We then evaluated if AR was associated with changes in LV strain using speckle-tracking 2D echocardiography. Global longitudinal strain remained similar between AR and sham animals. Circumferential strain was negatively modulated by AR but only in females and early after VO induction (13% (M) vs. 26% (F)). CONCLUSION: AR resulted in more LV dilation and quicker wall thickening in female AR rats compared to males. Global circumferential strain was negatively modulated in AR females but not in males. AR also seemed to lead to a more spherical LV shape in females whereas; it kept mostly an ellipsoid shape in males. This can influence validity of mass estimation of the dilated LV in females by echocardiography.

Attenuated Mitral Leaflet Enlargement Contributes to Functional Mitral Regurgitation After Myocardial Infarction.

BACKGROUND: Mitral leaflet enlargement has been identified as an adaptive mechanism to prevent mitral regurgitation in dilated left ventricles (LVs) caused by chronic aortic regurgitation (AR). This enlargement is deficient in patients with functional mitral regurgitation, which remains frequent in the population with ischemic cardiomyopathy. Maladaptive fibrotic changes have been identified in post-myocardial infarction (MI) mitral valves. It is unknown if these changes can interfere with valve growth and whether they are present in other valves. OBJECTIVES: This study sought to test the hypothesis that MI impairs leaflet growth, seen in AR, and induces fibrotic changes in mitral and tricuspid valves. METHODS: Sheep models of AR, AR + MI, and controls were followed for 90 days. Cardiac magnetic resonance, echocardiography, and computed tomography were performed at baseline and 90 days to assess LV volume, LV function, mitral regurgitation and mitral leaflet size. Histopathology and molecular analyses were performed in excised valves. RESULTS: Both experimental groups developed similar LV dilatation and dysfunction. At 90 days, mitral valve leaflet size was smaller in the AR + MI group (12.8 ± 1.3 cm2 vs. 15.1 ± 1.6 cm2, p = 0.03). Mitral regurgitant fraction was 4% ± 7% in the AR group versus 19% ± 10% in the AR + MI group (p = 0.02). AR + MI leaflets were thicker compared with AR and control valves. Increased expression of extracellular matrix remodeling genes was found in both the mitral and tricuspid leaflets in the AR + MI group. CONCLUSIONS: In these animal models of AR, the presence of MI was associated with impaired adaptive valve growth and more functional mitral regurgitation, despite similar LV size and function. More pronounced extracellular remodeling was observed in mitral and tricuspid leaflets, suggesting systemic valvular remodeling after MI.

Effects of the loss of estrogen on the heart's hypertrophic response to chronic left ventricle volume overload in rats.

Aortic valve regurgitation (AR) can result in heart failure from chronic overloading of the left ventricle (LV). Little is known of the role of estrogens in the LV responses to this condition. The aim of the study was to compare LV remodeling in female rats with severe AR in absence of estrogens by ovariectomy (Ovx). In a first study, we investigated over 6 months the development of hypertrophy in four groups of female Wistar rats: AR or sham-operated (sham) and Ovx or not. Ovx reduced normal heart growth. As expected, volume overload (VO) from AR resulted in significant LV dilation (42% and 32% increase LV end-diastolic diameter in intact and Ovx groups vs. their respective sham group; p < 0.0001). LV weight was also significantly and similarly increased in both AR groups (non-Ovx and Ovx). Increase in stroke volume or cardiac output and loss of systolic function were similar between AR intact and AR Ovx groups compared to sham. We then investigated what were the effects of 17beta-estradiol (E2; 0.03 mg/kg/day) treatment on the parameters studied in Ovx rats. Ovx reduced uterus weight by 85% and E2 treatment restored up to 65% of the normal weight. E2 also helped normalize heart size to normal values. On the other hand, it did not influence the extent of the hypertrophic response to AR. In fact, E2 treatment further reduced LV hypertrophy in AR Ovx rats (41% over Sham Ovx + E2). Systolic and diastolic functions parameters in AR Ovx + E2 were similar to intact AR animals. Ovx in sham rats had a significant effect on the LV gene expression of several hypertrophy markers. Atrial natriuretic peptide (Nppa) gene expression was reduced by Ovx in sham-operated females whereas brain natriuretic peptide (Nppb) expression was increased. Alpha (Myh6) and beta (Myh7) myosin heavy chain genes were also significantly modulated by Ovx in sham females. In AR rats, LV expression of both Nppa and Nppb genes were increased as expected. Ovx further increased it of AR rats for Nppa and did the opposite for Nppb. Interestingly, AR in Ovx rats had only minimal effects on Myh6 and Myh7 genes whereas they were modulated as expected for intact AR animals. In summary, loss of estrogens by Ovx in AR rats was not accompanied by a worsening of hypertrophy or cardiac function. Normal cardiac growth was reduced by Ovx in sham females but not the hypertrophic response to AR. On the other hand, Ovx had important effects on LV gene expression both in sham and AR female rats.

Sex differences in the response to angiotensin II receptor blockade in a rat model of eccentric cardiac hypertrophy.

Background. Men and women differ in their susceptibility to cardiovascular disease, though the underlying mechanism has remained elusive. Heart disease symptoms, evolution and response to treatment are often sex-specific. This has been studied in animal models of hypertension or myocardial infarction in the past but has received less attention in the context of heart valve regurgitation. The aim of the study was to evaluate the development of cardiac hypertrophy (CH) in response to left ventricle (LV) volume overload (VO) caused by chronic aortic valve regurgitation (AR) in male and female rats treated or not with angiotensin II receptor blocker (ARB), valsartan. We studied eight groups of Wistar rats: male or female, AR or sham-operated (sham) and treated or not with valsartan (30 mg/kg/day) for 9 weeks starting one week before AR surgical induction. Results. As expected, VO from AR resulted for both male and female rats in significant LV dilation (39% vs. 40% end-diastolic LV diameter increase, respectively; p < 0.0001) and CH (53% vs. 64% heart weight increase, respectively; p < 0.0001) compared to sham. Sex differences were observed in LV wall thickening in response to VO. In untreated AR males, relative LV wall thickness (a ratio of wall thickness to end-diastolic diameter) was reduced compared to sham, whereas this ratio in females remained unchanged. ARB treatment did not prevent LV dilation in both male and female animals but reversed LV wall thickening in females. Systolic and diastolic functions in AR animals were altered similarly for both sexes. ARB treatment did not improve systolic function but helped normalizing diastolic parameters such as left atrial mass and E wave slope in female AR rats. Increased LV gene expression of Anp and Bnp was normalized by ARB treatment in AR females but not in males. Other hypertrophy gene markers (Fos, Trpc6, Klf15, Myh6 and Myh7) were not modulated by ARB treatment. The same was true for genes related to LV extracellular matrix remodeling (Col1a1, Col3a1, Fn1, Mmp2, Timp1 and Lox). In summary, ARB treatment of rats with severe AR blocked the female-specific hypertrophic response characterized by LV chamber wall thickening. LV dilation, on the other hand, was not significantly decreased by ARB treatment. This also indicates that activation of the angiotensin II receptor is probably more involved in the early steps of LV remodeling caused by AR in females than in males.

Testosterone deficiency reduces cardiac hypertrophy in a rat model of severe volume overload.

The aim of the study was to characterize if the development of cardiac hypertrophy (CH) caused by severe left ventricle (LV) volume overload (VO) from chronic aortic valve regurgitation (AR) in male rats was influenced by androgens. We studied Wistar rats with/without orchiectomy (Ocx) either sham-operated (S) or with severe AR for 26 weeks. Loss of testosterone induced by Ocx decreased general body growth. Cardiac hypertrophy resulting from AR was relatively more important in intact (non-Ocx) animals than in Ocx ones compared to their respective S group (60% vs. 40%; P = 0.019). The intact AR group had more LV dilation, end-diastolic LV diameter being increased by 37% over S group and by 17% in AROcx rats (P < 0.0001). Fractional shortening (an index of systolic function) decreased only by 15% in AROcx compared to 26% for intact AR animals (P = 0.029). Changes in LV gene expression resulting from CH were more marked in intact rats than in AROcx animals, especially for genes linked to extracellular matrix remodeling and energy metabolism. The ratio of hydroxyacyl-Coenzyme A dehydrogenase activity over hexokinase activity, an index of the shift of myocardial substrate use toward glucose from the preferred fatty acids, was significantly decreased in the AR group but not in AROcx. Finally, pJnk2 LV protein content was more abundant in AR than in AROcx rats, indicating decreased activation of this stress pathway in the absence of androgens. In summary, testosterone deficiency in rats with severe LV VO resulted in less CH and a normalization of the LV gene expression profile.

[Values related to the occupational therapy profession: Identifying them to better define them]. / Valeurs liées à la profession d'ergothérapeute : les répertorier pour les définir.

BACKGROUND.: Inaccuracies and conceptual confusion characterize the literature on the values associated with occupational therapy. PURPOSE.: The purpose of this study was to identify values related to occupational therapy, propose definitions for those values, and validate the content of the definitions. METHOD.: A review of the literature ( n = 52) and consultation of occupational therapists ( n = 26) were used to document and define a series of values. The resulting list of values was tested for functionality by occupational therapists ( n = 5) and presented to occupational therapists with ethics expertise ( n = 6) to assess content validity of the value definitions. FINDINGS.: The proposed list presents 33 values with their definitions that the experts considered to be clear and representative of the realities they describe. The results show that the list is considered exhaustive. IMPLICATIONS.: This study identified values that are ideals that can guide occupational therapy practice and support the claims and cultural and ethical competencies of occupational therapists.

DESCRIPTION.: Des imprécisions et des confusions conceptuelles caractérisent les écrits sur les valeurs liées à l'ergothérapie. BUT.: Répertorier des valeurs liées à l'ergothérapie, proposer des énoncés qui les définissent et procéder à leur validation de contenu. MÉTHODOLOGIE.: Une recension des écrits ( n = 52) et la consultation d'ergothérapeutes ( n = 26) ont permis de documenter et de définir une série de valeurs. Le répertoire issu de ces démarches a été soumis à un test de fonctionnalité auprès d'ergothérapeutes ( n = 5), puis présenté à des ergothérapeutes détenant une expertise en éthique ( n = 6) pour en évaluer la validité de contenu des définitions des valeurs. RÉSULTATS.: Le répertoire proposé comprend 33 valeurs suivies de leur définition que les experts ont jugées claires et représentatives des réalités qu'elles désignent. Les résultats montrent que le répertoire est considéré comme exhaustif. CONSÉQUENCES.: Cette étude a permis de répertorier et de définir des valeurs qui constituent des idéaux susceptibles de guider la pratique ergothérapique et de soutenir les revendications ainsi que les compétences culturelles et éthiques des ergothérapeutes.

Multiple short-chain dehydrogenases/reductases are regulated in pathological cardiac hypertrophy.

Cardiac hypertrophy (CH) is an important and independent predictor of morbidity and mortality. Through expression profiling, we recently identified a subset of genes (Dhrs7c, Decr, Dhrs11, Dhrs4, Hsd11b1, Hsd17b10, Hsd17b8, Blvrb, Pecr), all of which are members of the short-chain dehydrogenase/reductase (SDR) superfamily and are highly expressed in the heart, that were significantly dysregulated in a rat model of CH caused by severe aortic valve regurgitation (AR). Here, we studied their expression in various models of CH, as well as factors influencing their regulation. Among the nine SDR genes studied, all but Hsd11b1 were down-regulated in CH models (AR rats or mice infused with either isoproterenol or angiotensin II). This regulation showed a clear sex dimorphism, being more evident in males than in females irrespective of CH levels. In neonatal rat cardiomyocytes, we observed that treatment with the α1-adrenergic receptor agonist phenylephrine mostly reproduced the observations made in CH animals models. Retinoic acid, on the other hand, stimulated the expression of most of the SDR genes studied, suggesting that their expression may be related to cardiomyocyte differentiation. Indeed, levels of expression were found to be higher in the hearts of adult animals than in neonatal cardiomyocytes. In conclusion, we identified a group of genes modulated in animal models of CH and mostly in males. This could be related to the activation of the fetal gene expression program in pathological CH situations, in which these highly expressed genes are down-regulated in the adult heart.

Loss of OcaB Prevents Age-Induced Fat Accretion and Insulin Resistance by Altering B-Lymphocyte Transition and Promoting Energy Expenditure.

The current demographic shift toward an aging population has led to a robust increase in the prevalence of age-associated metabolic disorders. Recent studies have demonstrated that the etiology of obesity-related insulin resistance that develops with aging differs from that induced by high-calorie diets. Whereas the role of adaptive immunity in changes in energy metabolism driven by nutritional challenges has recently gained attention, its impact on aging remains mostly unknown. Here we found that the number of follicular B2 lymphocytes and expression of the B-cell-specific transcriptional coactivator OcaB increase with age in spleen and in intra-abdominal epididymal white adipose tissue (eWAT), concomitantly with higher circulating levels of IgG and impaired glucose homeostasis. Reduction of B-cell maturation and Ig production-especially that of IgG2c-by ablation of OcaB prevented age-induced glucose intolerance and insulin resistance and promoted energy expenditure by stimulating fatty acid utilization in eWAT and brown adipose tissue. Transfer of wild-type bone marrow in OcaB-/- mice replenished the eWAT B2-cell population and IgG levels, which diminished glucose tolerance, insulin sensitivity, and energy expenditure while increasing body weight gain in aged mice. Thus these findings demonstrate that upon aging, modifications in B-cell-driven adaptive immunity contribute to glucose intolerance and fat accretion.

Early Activation of Growth Pathways in Mitral Leaflets Exposed to Aortic Regurgitation: New Insights from an Animal Model.

BACKGROUND AND AIM OF THE STUDY: Mitral leaflet enlargement in patients with chronic aortic regurgitation (AR) has been identified as an adaptive mechanism potentially able to prevent functional mitral regurgitation (FMR) in response to left ventricular (LV) dilatation. The timing of valve enlargement is not known, and the related mechanisms are largely unexplored. METHODS: AR was induced in 58 rats, and another 54 were used as sham controls. Animals were euthanized at different time points after AR creation (48 h, one week, and three months), and AR severity, FMR and LV dilatation were assessed using echocardiography. Mitral valves were harvested to document the reactivation of embryonic growth pathways. RESULTS: AR animals had increased LV dimensions and mitral annulus size. No animal developed FMR. No change in leaflet length or thickness was seen at 48 h; however, anterior mitral leaflets were longer and thicker in AR animals at one week and three months. Molecular changes were present early (at 48 h and at one week), with positive staining for transforming growth factor-b1 (TGF-b1), Alpha-smooth muscle actin (α-SMA) and matrix metalloproteinase-2 (MMP-2), which suggested active matrix remodeling. Increased gene expression for collagen 1, TGF-ß1, α-SMA and MMP-2 was found in the mitral valve at 48 h and at one week, but after three months their expression had returned to normal. CONCLUSIONS: This model of AR induces active expansion and thickening of the mitral leaflets. Growth signals are expressed acutely, but not at three months, which suggests that most of this enlargement occurs at an early stage. The stimulation of valvular growth could represent a new strategy for the prevention of FMR.